Conventional marking instruments, such as markers, pens, and correction fluid dispensers, typically include a writing tip fluidly connected to a reservoir adapted to store and supply ink or other fluids. Conventional markers incorporating capillary and free fluid reservoirs are generally not suitable for dispensing fluids with viscosities above 5 cp (centipoise). In particular, capillary and free fluid reservoir markers are prone to clogging and low-flow conditions when dispensing high viscosity fluids (e.g., fluids with viscosities greater than 5 cp) because the flow-rates are insufficient for supplying ink or other fluids at normal writing and marking speeds.
FIG. 1 illustrates an exemplary prior art marker 10 having a hollow body 12, a sealing cap 14 and a writing section 16. The body 12 includes a first end 18 adapted to cooperate with the sealing cap 14 to form a cylindrical reservoir. The sealing cap 14 may fixedly or removable attach to the body 12 using a variety of known manufacturing techniques such as, for example, a snap or interference fit system, friction welding the two components together, applying an adhesive to secure the components, and integrally forming a pair of complimentary threaded fasteners into the structure of the two components. Other known markers include the body 12 and sealing cap 14 formed or molded into a single piece during the manufacturing process.
The body 12 further includes a second end 20 distal to the first end 18 and the sealing cap 14. The second end 20 cooperates with the writing section 16 to seal the reservoir and marker 10. The writing section 16 attaches to the second end 20 using any of the manufacturing techniques described in connection with the sealing cap 14. It will be understood that the sealed cylindrical reservoir can be a pressurized reservoir, an unpressurized reservoir, or a capillary reservoir, depending on the intended writing application. Regardless of the chosen reservoir type, the sealed reservoir stores and contains a liquid such as ink, marking fluid and correction fluid dispensable by the writing section 16.
The writing section 16 includes an adaptor ring 22 secured to the second end 20 of the body 12. The adaptor ring 22 may include, for example, an internal friction or bonding surface (not shown) adapted to securely engage the second end 20 to fixedly attach the writing section 16. A generally cone-shaped transition surface 24 integrally connects the adaptor ring 22 to a mounting surface 26 formed distal to the second opening 20.
A marker nib 28 having an integral marker point 30 can, in turn, attach within a receiving pocket (not shown) formed in the mounting surface 26. The receiving pocket secures the marker nib 28 and provides a fluid connection between the liquid stored within the fluid reservoir and the marker point 30. The marker nib 28 and the marker point 30 may be manufactured from a variety of permeable fibrous materials and formed into numerous shapes such as, for example, a rounded point, a knife-shaped wedge, or a cylindrical tip. In addition, a cap 32 removeably engages the transition surface 24 and/or the adaptor ring 22 to protect the marker nib 28 and the marker point against damage, drying, etc.
The body 12 may include a distended pumping portion (not shown) formed adjacent to the writing section 16. The distended pumping portion forms a balloon-like structure adapted to increase the pressure within the body 12 when the balloon-like structure is squeezed. It will be understood that irregularly shaped reservoirs, such as a kidney shaped reservoir, an oval shaped reservoir, and a triangular shaped reservoir may have a single opening for filling and ultimately dispensing the stored liquids.
FIG. 2 illustrates an alternate embodiment of a prior art marker 40 including a second writing section 42 affixed adjacent to the first end 18. Thus, the second writing section 42 cooperates with the hollow body 12 and the first writing section 16 to form the double ended marker 40. In use, the double ended marker 40 produces multiple line thicknesses because the first writing section 16 is configured to produce a narrow or fine line, while the second writing section 42 is configured to produce a bold or wide line
Similar to the first writing section 16, the second writing section 42 fixedly or removably attaches to the first end 18 of the body 12 using an adaptor ring 44. The second writing section 42 includes an oversized marker nib 46 having an oversized writing point 48 formed distal to the adaptor ring 44. In operation, the second writing section 42 cooperates with the fluid reservoir to produce a bold or wide line by dispensing a high volume of the stored liquid. As previously discussed, the oversized marker nib 46 and writing surface 48 are typically formed from permeable fibrous materials intended to dispense the stored liquid. In addition, a cap 50 may engage a transition surface 52 integrally formed with the adaptor ring 44 to provide protection for the marker nib 46.